textproduct: Rapid City

KEY MESSAGES

- Critical fire weather conditions continue through this evening with a RED FLAG WARNING in effect for northeast Wyoming, the Black Hills, and southwestern South Dakota through 10 PM MDT.

- A few light rain showers and breezy conditions are expected Thursday with high temperatures 30 degrees cooler than today, only topping out in the 40s and 50s.

- A warming and drying trend returns for Friday through Monday, with low forecast confidence thereafter.

UPDATE

Issued at 933 PM MDT Wed Mar 25 2026

Main change to the previous forecast was to raise pops tonight into Thursday and lower temps the next couple days. Potent jet streak will settle south overnight as a sfc cold front does the same. Entrance region of the jet, ample Pac moisture, and strong FGEN forcing will support bands of precip through Thur, esp across NW SD. Rain will change to or mix with snow across NW SD and the higher elevations of the BH Thur, with accums up to an inch possible in those locations. Given precip and clouds, lowered highs Thur a few degrees (in line with hires trends), esp across the western third. Did the same for lows Thur night and highs Fri as a decent batch of CP air will settle over the region.

DISCUSSION

(This Evening Through Wednesday) Issued at 211 PM MDT Wed Mar 25 2026

A combination of record warm temperatures, gusty winds, low relative humidities, and ongoing drought will continue to support yet another period of critical fire weather conditions through this evening, and the ongoing RED FLAG WARNING remains unchanged and in effect through 10 PM across northeast Wyoming, the Black Hills, and portions of southwestern South Dakota. The highest confidence in these conditions remains across southern Campbell and Weston counties in Wyoming down across Custer and Fall River counties in South Dakota, where a few stations have already reported wind gusts in excess of 30 MPH and RH values as low as 14 percent early this afternoon. Keep in mind that even where humidity values remain closer to 20 percent, it won't make any meaningful difference in the risk of fire spread with extremely dry fuels in place.

Cooler, more humid air takes hold of the region tonight and Thursday, with breezy conditions and a chance of light rain showers spreading in from north to south starting generally after midnight tonight. Showers may reach as far south as Gillette, Rapid City, and Philip through the morning, spreading further south during the afternoon. Activity will be isolated to scattered for most areas. A few models (such as the HRRR) have trended quite a bit wetter/more impressive with this activity, but consensus across the full model suite in both placement and QPF remains limited. Have blended in some slightly higher QPF across roughly the northern half of the CWA into the Black Hills, but our official forecast remains less than one-tenth of an inch. Wouldn't be surprised to see a few isolated totals reach that 0.10" threshold, especially from the Black Hills up across the northwestern South Dakota plains, with the driest conditions across the counties bordering Nebraska.

Another feature we're noting in today's guidance is some sort of secondary cold front/secondary push of cold air advection Thursday evening into Friday morning. A few models such as the NAM and HRRR are carrying NW wind gusts of 40 MPH for at least several hours with this push, while most guidance does more universally show a notable increase in winds aloft at 700mb (as high as 50kts off the GFS!). This feature and attendant wind increase is washed out completely by the various model inputs blended into the NBM, and not every model brings stronger gusts to the surface. Simulated reflectivity off the HREF members may be picking up on this feature as well. Confidence is currently low in how much surface gusts may increase, but this will be a period we'll continue to evaluate in future forecast updates.

Overall forecast confidence Friday through Monday is high with a general warming/drying trend expected...supported by modest amplification of a synoptic ridge of high pressure. Near-critical fire weather conditions will be possible once again for some areas each day. Confidence starts to waver by Monday night/Tuesday, however, as multiple organized low pressure features of interest invade Canada and the western US with large discrepancies across the long-range deterministic models. A breezier and more active period precipitation-wise seems possible, likely continuing through the end of next week.

AVIATION

(For the 06Z TAFS Through 06Z Thursday Night) Issued At 1034 PM MDT Wed Mar 25 2026

VFR conditions through most of tonight. Light rain (and some high elevation snow) will develop across the area Thursday morning across northeast WY and western SD. MVFR (local IFR) cigs will develop Thur morning in NE upslope flow. Breezy north winds can be expected behind a cold front tonight, continuing into Thur.

FIRE WEATHER

Issued At 211 PM MDT Wed Mar 25 2026

A combination of record warm temperatures, gusty winds, low relative humidities, and ongoing drought will continue to support yet another period of critical fire weather conditions through this evening, and the ongoing RED FLAG WARNING remains unchanged and in effect through 10 PM across northeast Wyoming, the Black Hills, and portions of southwestern South Dakota. The strongest winds and lowest RH values will overlap across southern Campbell and Weston counties in Wyoming down across Custer and Fall River counties in South Dakota, where a few stations have already reported wind gusts in excess of 30 MPH and RH values as low as 14 percent early this afternoon. Winds will be lighter across the western South Dakota plains, although occasional gusts greater than 25 MPH are possible during peak heating this afternoon. Keep in mind that even where humidity values remain closer to 20 percent, it won't make any meaningful difference in the risk of fire spread with extremely dry fuels in place.

Winds shift into the northwest tonight with a much cooler, more humid airmass in place for Thursday, although NW wind gusts of 20 to 30 MPH are expected much of the day across the region. While confidence is low, a several hour increase in those gusts is possible between Thursday evening and Friday morning as a reinforcing shot of cooler air pushes into the region. The good news is RH values should bottom out at 30-40 percent Thursday afternoon despite the breezy conditions. A warming/drying trend returns for Friday through Monday with afternoon RH values back to 10-20 percent and afternoon wind gusts potentially approaching 25 MPH at times, thus another period of near-critical fire weather conditions.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.